用随机模拟方法研究设定地震地面运动

Study on the ground motion of scenario earthquake using stochastic simulation method

用随机模拟方法研究设定地震地面运动可分两步进行：（1）采用中小地震的数字观测资料确定研究区路径、场地参数；（2）把确定的参数应用到研究区的强地面运动随机模拟中．为此，本文首先采用了一种可行的方法，分离软基岩场地效应和非弹性衰减的影响，并把二者分别确定出来．研究区北部中软基岩场地的平均效应在2～4Hz频率范围为1．5倍左右；研究区的S波品质因子为Qs=278f^0．346．把这些参数用于研究区的场地和路径模型中，并选择单拐角频率震源谱模型，随机模拟了研究区未来中强地震可能在北天山中段可能造成的地面运动，模拟加速度时程和反应谱可以服务于本地区的地震灾害预测和建筑物可靠性验算．

Studying the ground motions of scenario earthquake using stochastic simulation method needs two steps. （1）Using digital seismic data of small-moderate earthquake to study the parameters of path and site. （2） Applying the determined parameters to stochastic simulation of ground motion. For that, we firstly use a feasible method to separate the site effect of soft rock and the anelastic attenuation of path. The average site effect of soft rock in the northern part of the research region reaches 1.5 or so in 2 - 4Hz. The S wave quality factor of the research region is obtained as Qs = 278f^0.346 . Secondly, we apply these parameters to the model of site and path in the region, and choose source spectrum of single comer frequency. Then, we simulate the possible ground motions of the middle area of Northern Tianshan from future moderate-strong earthquakes in the research region. The resultant acceleration histories and spectra of ground motions may serve for evaluating earthquake disaster and checking the reliability of buildings in this region.